Water purification



,l' atented July 2!, i925.

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Be it known that I, ALFRED N. Fnm, a'

citizen of the United States, residing at- Washington, in the"Districtof have invented a certain new and-nee ff Improvement in WaterPurification,

which the following is a.- full, clear, and exact description. fyThisinvention relates to this;1 art of'- uri or softemng. "water 'su as no.Willis for industria;l the; "in boilers laundries, textile and pe rindustries, in

other industries where s ts other than salts of the alkali metals'areobjectionable and it consists in-treating the waterhefore it is to be toremove the objectionable ma An object of this invention is to so treatthe water that practimlly all theisalts in solution objectionablegualities are removed before the water is use Y {Another object .of'this invention is to treat the; water with such chemicals thatsubstantially all the objectionable ingredients are removed and yet thewater can-.

not be over-treated, that is cannot take 11 any substantial --a. mountof the chemica with which it is treated.

4 further 0 ject of the invention is. to provide a simp e and method oitreatmg natural vzgtersnwtlii is relatively inexpensive in 1 opera. on.

Another phuric acid ofsnbstantiall' .all the sulphate salts whether theybe sal alkaline earth or alkali metals..

according t m m; ess one may roceed with the two steps of the reaction ycarry taneously or in op onal succewion, dependof the upon theconditionsand un er which the process is being. o rated,. as will appear morefully herema r, but I will first describe these steps of the proceesindividually.

application ille'd 'ianuary 18, 1928. Be rial No. 815,768.

'c' of the ihve'ntion possible'toremove substan y-all the ing them outs1mul- To remove the bicarbonates or tengforary hardness first, I treatthe water by terin it through a filter containing an excess '0 magnesiumoxide, hydroxide or its equiv alent, to react with the bicar on'ates,trans forming them into the respective carbonates. Or if it be desired,the ma its equivalent can be 'adde agitated and the recipitate removed.

. For each molec e transformed, one molecule of a magnesium carbonate isformed from the magnesia. or its uivalent according to' the followingequa one:

The calcium' and magnesium "carbonates -formed -from their. respectivebicarbonates andfrom the magnesia involved in this re action arerelatively insoluble and there"- esium oxide or and the. water a foreform precipitates. If there be any sodium in it forms magnesiumcarbonatehydroxide] and haps some sodium cars bona-te because 1; e reactions maynot to completion both of which being solub e are retained in solution.If there .be an b1- umi-" carbonates, such a's-those ofiron or num, theyare also precipitated and moved during-this ste -of the process.

Intrea 7 thewater-to'remove. the Billesire to u'seflan alkalm'e..earthcarbonate,

referably in excess, such.',-"for'exam le, as Barium carbonate whichreacts with t e 's'ulcarbonate present in the water,

y innatural' wate'rI.

phates in solution to formbarium sulphate and therespective carbonatesof, the metals;

previously existing as a' Spch sulphates usually are calcium, magnesiumor sodium sulphates. In the case of the calcium and magnesium sulphates,the barium carbonate reacts to form barium sulphate and calcium andmagnesium carbonates, all of which are relatively insoluble and-arecording tothe following equations e CaS0,-BaOO,=BaSO,-C&CO, NasO-BaOQiliasO -Naflo,

precipitated. These reactions take place 'ac-' In the case of sodiumsulphate, the reaction forms barium ,sul ate which is relativelyinsoluble and sodium-carbonate which remains in solution.

The majority of waters to be treated contain only normal amounts ofbicarbonates with variable amounts of sulphates and with these eithertreatment can be used first but preferably the barium carbonate. If,however, the water to be treated contains more carbon dioxide insolution than nor- 'p mal surface waters, it may be preferable to treatthis water with the ma esium compound first. This is because t e excesscar on dioxide in solution would tend to dissolve a relatively largeramount of barium carbonate, which even though small is usuallyundesirable and it would have to be removed later. Also, if the water tobe treated to be a itated with the added in an atmosphere havingchemical instead 0 filtered through a bed containing it and if the wateris of such a nature that it is more desirable to treat with the bariumcarbonate in the second step, this second stepshouldb'e carried out nocarbon dioxide because its presence wil c ause apartial solution of thebarium carbonate and this is objectionable for some purposes.

If the water to be treated contains large amounts of Sn] hates insolution, it is preferable to treat it with the barium carbonate firstin order to precipitate a larger quantity of salts first, also becauseit has been found that the sulphates are more readily precipitated whilebicarbonates are sti present. In order to get the best results themagnesium oxide should be prepared with special reference to thefineness and temperature of burning, as is well understood, so that itwill be active chemically when added for treatment. The barium carbonateused in connection with the reaction with the sulphates is a product nowobtainable .in .commercial quantities on the market. I

The small amounts of sodium carbonate and hydroxide which remaininsolution as.

. a. r'esult of the reactions, render the solution slightly alkaline andthis is not only not in urious for most-purposes, but is actuallybeneficial to boilers, valves, pipes, etc., of the system where it isused.

It may be noted that the chemicals added for treatment may; be added tothe water and the water agitated to ensure complete reactions, or thewater may be run throu h suitable filters containing thechemicals ortreatment. In the former case the recipitated material may be removed bytration or sedimentation and in the lauer case the precipitates will beremoved as formed. In either case the sus nded matter i'n'the watercomes down with the precipitate and is removed at the same time.

It will also be noticed that in treating water according to my rocessthat one does not need to be carefu about the amount of magnesium orbarium salts added except to transform them into a that there must be asufiicientf minimum amount to properl react with the salts in solution.This is because aniexccss of the added materials can not increase thesoluble mineral contents of the water but they are substantially reducedafter treating with my rocess.

Attention is also'directcd to the fact that in removing the bicarbonatesand sulphates substantially all the scale forming compounds are removed,.so that my process may be operated to advantage in treating waters foruse in boilers, as well as". for ma ny other industrial applications anduses.

It will be seen, also, that my roc'ess resents a simple, cheap andellicient' met iod of treating in "large quantities s. large variety ofnatural waters. These waters may be treated at their source, or wherethey are wanted lor use, without a large investment in a hint and yetthe treated water will be rec from all objectionable mineral contents.

It may also be noted that for waters in which'a relatively smallquantity of the bicarbonates and sulphates occur that the treatingagents employed may be used to react simultaneously-with the saltsoccurring in the water and the resulting precipitates removed.

F urtherinorc, it is to be understood that the particular com undsdisclosed, and the procedure set fort 1;, are presented for pur-- posesof explanation'and illustration and that "arious e uivalents can be usedand modifications oi said procedure can be made. without departing frommy invention as defined in the appended claims.

Having described my invention, claim is: i a

1. The process of softening water which consists in treating it with analkaline earth oxide, capable of decomposing bicarbonates and with acarbonate capable of preci 'itating sulphates and ,reactin with alkalisalts ali carbonates.

purifying water which consists in treating the water with a carbonatecapable of reactin with the sulphates what I '2. The process of to formrelatively inso ubleprecipitates ad with an oxide capable pfreactmg withb1.-

carbonates and removing the precipitates from the solution. r

3. The process of purifying water which consists in treatingit-with acompound-capable of media with bicarbonates and with a corbonate caps 1eof reactin with alkaline earth sulphates-to form relatively insolublesulphates and carbonates, and removing the insoluble compounds from thesolution.

4. The recess of purifying water for boilers which consists in treatingit with a cofipound capable of reactin with alkaline ea bicarbonatesto-form re atively insoluble carbonates, and with a carbonate capable ofreacting with alkaline'earth sulphates to form relatively insolublesulphates, and reacting with alkali sulphates to precipitate insolublesulphates and form alkali carbonates, thereb precipitating substantiallyall objectionab e mineral compounds.

5. The process of softening water which consists in treating it with anoxide capable of reacting with bicarbonates, other than alkalibicarbonates, to form relatively in-. soluble carbonates and treatingwith an alkaline earth carbonate capable of reacting with sulphates in'the water, other than alkali sulphates, forming relatively insolublecarbonates and insoluble sulphates and removing such precipitates fromthe water.

6. The process of purifying water which consists in treating it with analkaline earth carbonate to react with alkaline earth sulphates to formrelatively insoluble sulphates and with an alkaline earth oxide capableof reacting with alkaline earth bicarbonates to form relativelyinsoluble carbonates and removing such relatively insoluble compounds.

7. The process of purifying water for boilers and the like whichconsists in treat ing it with magnesium oxide and an alkaline earthcarbonateto react with the bicarbonates and sul hates in solution,forming relatively insolu ble alkaline earth carbonates and sulphates,said magnesium oxide and alkaline earth carbonate also reacting withalkali bicarbonates and sulphates to form alkali carbonates andhydroxides.

8. The process of softening water which consists in treating it withmagnesium oxide and barium carbonate, the ma nesLum oxide reactin withalkaline earth bicarbonates to form re atively insoluble alkaline earthcarbonates in water, and reacting with'alkali bicarbonates' to formalkali carbonates and hydroxides, said barium carbonate reacting withalkaline earth sulphates to form barium sulphateand alkaline earthcarbonates, and also reacting with alkalisulphates to form bariumsulphate, and removing the relaprecipitates and suspended matter,

precipitates from the water.

-9. The process of purifying water which consists in treating it with analkaline earth carbonate in excess to form relativel insoluble alkalineearth sulphates and 'al ali carbonates and treating it with magnesiumoxide in excess to react with the bicarbonates to form relativelyinsoluble carbonates.

10. The process ofpurifying water which consists in treating it inoptional succession with milk of magnesia in excess to react with thebicarbonates to form relatively insoluble carbonates and with bariumcarbonate inexcess to form relatively insoluble alkaline earthsulphates. r

11. The process of purifyingi water which consists in treating it withmil of magnesia and barium carbonate, both in excess, and removing theprecipitates.

12. The process of purifying water which consists in removing the acidradical of all the sulphate salts in the water, decomposing thebicarbonates in the water and removing substantially all the carbonatesby treating with barium carbonate and milkof magnesia and removing theprecipitates formed.

13. The process of purifyin water which consists in 'rcmovin from tiewater the salts of heavy metafii and the sulphates b treating the waterwith an oxide and Witl i an alkaline earth carbonate and removing theprecipitates formed.

14. The process of urifyin water for boilers and the like which consistsin treating it with magnesium oxide and barium tively insolublecarbonate to react with the bicarbonates and sulphates in solution,forming relatively insoluble alkaline earth carbonates and sulphates andfiltering the water to remove the whereby substantially all the scaleforming compounds are removed.

In testimony whereof, I hereunto aflix my signature.

ALFRED N. FINN.

of reacting with alkaline earth sulphates to form relativel insolublesulphates, and reacting with alkali sul hates to precipitate insolublesulphates an form alkali carbonates, thereb precipitating substantiallyall objectionab e mineral compounds.

5. The process of softening water which consists in treating it with anoxide capable of reacting with bicarbonates, other than alkalibicarbonates, to form relatively in-. soluble carbonates and treatingwith an alkaline earth carbonate capable of reacting with sulphates in'the water, other than alkali sulphates, forming relatively insolublecarbonates and insoluble sulphates and removing such precipitates fromthe water.

6. The process of purifying water which consists in treating it with analkaline earth carbonate to react with alkaline earth sulphates to formrelatively insoluble sulphates and with an alkaline earth oxide capableof reacting with alkaline earth bicarbonates to form relativelyinsoluble carbonates and removing such relatively insoluble compounds.

7. The process of purifying water for boilers and the like whichconsists in treating it with magnesium oxide and an alkaline earthcarbonateto react with the bicarbonates and sulphates in solution,forming relatively insoluble alkaline earth carbonates and sulphates,said magnesium oxide and alkaline earth carbonate also reacting withalkali blCtlIbOIlfl-lJBS and sulphates to form alkali carbonates andhydroxides.

8. The process of softening water which consists in treating it withmagnesium oxide and barium carbonate, the magnesium oxide reacting withalkaline earth bicarbonates to form relatively insoluble alkaline earthcarbonates in water, and reacting with alkali bicarbonates to formalkali carbonates and hydroxides, said barium carbonate reacting withalkaline earth sulphates to form barium sulphate'and alkaline earthcarbonates, and also reacting with alkali sulphates to form bariumsulphate, and removing the relatively insoluble precipitates from thewater.

9. The process of purifying water which consists in treating it with analkaline earth carbonate in excess to form relativel insoluble alkalineearth sulphates and a1 ali carbonates and treating it with m esium oxidein excess to react with the bicarbonates to form ielatively insolublecarbonates.

10. The process of purifying water which consists in treating it inoptional succession with milk of magnesia in excess to react with thebicarbonates to form relatively insoluble carbonates and with bariumcarbonate in excess to form relatively insoluble alkaline earthsulphates.

11. The process of purifyin water which consists in treating it with milof magnesia and barium carbonate, both in excess, and removing theprecipitates.

12. The process of purifying water which consists in removing the acidradical of all the sulphate salts in the water, decomposing thebicarbouates in the water and removing substantially all the carbonatesby treating with barium carbonate and milkof ma nesi'a and removing theprecipitates formed.

13. The process of purifyin water which consists in rciuovin from t ewater the salts of heavy meta s and the sulphates b treating the waterwith an oxide and Wit an alkaline earth carbonate and removing theprecipitates formed.

14. The process of urifyin water for boilers and the like which consistsin treating it with magnesium oxide and barium carbonate to react withthe bicarbonates and sulphates in solution, forming relatively insolublealkaline earth carbonates and sulphates and filtering the water toremove the precipitates and suspended matter whereby substantially allthe scale forming compounds are removed.

In testimony whereof, I hereunto aflix my signature.

ALFRED N. 'FINN.

V g Certificate of Correction. It is hereby certified that in LettersPatent No. 1,547,111. granted July 21.. 1925,

upon the application of Alfred Finn, a n improyement in WaterPurification? tion requiring correction as follows Page the word inwater and-line 41, after of W ashington District of Columbia, for

an error appears in the printed specifica- 3, line 40, claim 8, strikeout the words bicai'bonates insert the words in the water; andthat thesaid Letters Patent should be read with this correction therein that thesame may conform to the Signed and sealed this 22d day [snan] record ofthe case in the Patent Ofiice. of September, A, D. 1925.

y KARL FENNING,

Acting Commissioner of Patents.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,547,111. grantedJuly 21. 1925, upon the application of Alfred Y. Finn, ofhwhingtomlfistrict of Columbia, for an improvement in WaterPurification; an error appears in the printed specification requiringcorrection as follows: Page 3, line 40. claim 8, strike out the words inWater and line 41, after the word hicarhonates insert the words in thewater,- and that the said LettelePntent should be read with thiscorrection therein that the same may conform to the record of the arsein the Patent Office.

Signed and sealed this 22d day of September, A, D. 1925.

[SEAL] KARL FENNING,

A cting Uommz'sez'onor of Patents.

